Question

Major amount of water is selectively reabsorbed by the tubular part of the nephron. On what factor does the amount of water reabsorbed depend on?

Answer 1

From the tubular filtrate, active uptake of sodium and other ions take place which increases the water potential (solute potential becomes less negative), therefore equivalent amount of water leaves the tubular filtrate and passes into the blood capillaries by osmosis. Since water is absorbed by the process of osmosis, the factors that affect osmosis like concentration gradient, difference in water potential, pressure etc. would affect the absorption of water from proximal convoluted tubule.